Device for producing two-chamber containers

ABSTRACT

The invention relates to a two-chamber container, in particular as a non-resealable disposable packaging, wherein the two-chamber container has an inner chamber ( 1 ) and an outer chamber ( 2 ) surrounding the inner chamber ( 1 ), and a cap ( 3 ) produced by compression of plastics material, with which the upper edges of the wall of the inner chamber ( 1 ) and those of the outer chamber ( 2 ) are rigidly connected, the cap ( 3 ) having two separate channels ( 7   1   , 7   2 ), and the inner chamber ( 1 ) being arranged asymmetrically inside the outer chamber ( 2 ) in such a way that a portion of its wall is secured to the cap ( 3 ) in the region between the channels ( 7   1   , 7   2 ) in such a way that one channel ( 7   1   , 7   2 ) is connected to one of the chambers ( 1  or  2 ) in each case.

CROSS REFERENCE TO RELATED APPLICATIONS

Applicant claims priority under 35 U.S.C. §119 of German Application No.199 58 920.8, filed on Dec. 7, 1999. Applicant also claims priorityunder 35 U.S.C. §365 of PCT/EP00/12214, filed on Dec. 5, 2000. Theinternational application under PCT article 21(2) was not published inEnglish.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a device for producing two-chamber containers,with an inner mandrel and an outer mandrel, wherein the inner mandrelcan be inserted into and withdrawn from the outer mandrel, a die cavityfor a cap and a material feeder for supplying a heated portion of athermoplastic polymer material into the die cavity of a compressionmould.

2. The Prior Art

A device of this type is known from U.S. Pat. No. 5,219,373. Here, twoseparately produced one-piece tubes with different diameters are pushedonto their corresponding inner or outer mandrel respectively, so a capwith common outlet aperture is provided by means of injection mouldingowing to a nozzle piece and is simultaneously connected to both tubeends. This method is time-consuming as a result of the many individualsteps and, therefore, does not allow a high number of pieces to beproduced per unit of time, in particular as the tubes are initiallyproduced individually and have to be introduced into the device in acoordinated manner.

SUMMARY OF THE INVENTION

The object of the invention is to provide a device for producingtwo-chamber containers, in particular as non-resealable disposablepackaging, which looks nice and can be produced simply and quickly.

This object is achieved by a device for producing two-chambercontainers, with an inner mandrel and an outer mandrel, wherein theinner mandrel can be inserted into and withdrawn from the outer mandrel,a die cavity for the cap and a material feeder for supplying a heatedportion of a thermoplastic polymer material into the die cavity of acompression mould. There is a device for winding a film around thedriven-out inner mandrel and a device for winding a film around theouter mandrel and advanceable welding devices to produce longitudinalside seams to produce tubes. The mandrels can both be inserted into andwithdrawn from the die cavity of the compression mould to produce a capwith a seal and for connection to the walls of the chambers formed. Eachmandrel has a projection in the direction fo the die cavity for forminga channel in the cap connected to a chamber in each case.

In a preferred embodiment, the advanceable welding device has twoopposing and pivotable welding jaws which have two jaw projectionsseparated by a gap in each case, wherein a cutting device can beinserted into and withdrawn from the common gap.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in more detail below with the aid of anembodiment of a device for producing two-chamber containers.

In the drawing:

FIG. 1 shows a two-chamber container in side view;

FIG. 2 shows the two-chamber container illustrated in FIG. 1 in planview from above;

FIG. 3 shows a device for producing the two-chamber container inschematic view;

FIGS. 4 a, b, c shows a mandrel system and its interaction with apressing tool;

FIG. 5 shows a view from above onto the mandrel system with tubes;

FIG. 6 shows the supply of a strip of film round a mandrel for producinga side seam;

FIG. 7 shows the formation of a side seam on a film wound round amandrel and its separation from the strip of film.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The two-chamber container illustrated in FIG. 1 in the form of adisposable packaging for two components which are to be storedseparately from one another but are to be used together, has an innerchamber 1 and an outer chamber 2 surrounding it, a cap 3 and a fasteningseam 4 produced only after filling of the chambers 1 and 2 withdifferent filling components, which fastening seam seals the chambers 1,2 at the end remote from the cap 3 while separating them from oneanother.

The cap 3 has a shoulder 5 which, according to FIG. 2, has a laterallyflattened, rounded cross-section which can also be rounded so as to becircular or oval. The cap 3 also has a—in this case central—neck 6 inwhich two channels 7.sub.1, 7.sub.2 are formed, of which one in eachcase is connected to one of the chambers 1 or 2. A seal 8 is attached tothe neck 6, which seal is designed in the embodiment as a twist-off seal9. There is a predetermined breaking point 10 on part or all of theperiphery of the neck 6 in order to facilitate twisting off. Thetwist-off seal 9 is preferably designed in such a way that when it isbroken and the openings of the channels 7.sub.1, 7.sub.2 are thusexposed it remains connected to the cap 3, in other words, it does nothave to be disposed of separately.

The chamber 1 is produced from a tubular film 11 with smaller diameterand the outer surrounding chamber 2 from a tubular film 12 with largerdiameter. As shown clearly in FIGS. 1 and 2, the tubular film 11 issecured by a portion of its wall to the insert 13 arranged centrally inthis case, in which the channels 7.sub.1, 7.sub.2 are formed, so as toseparate them from one another in such a way that each chamber 1, 2 isconnected to only one channel 7.sub.1 or 7.sub.2.

The workstations for producing a two-chamber container, as is describedabove for example, can be seen in FIG. 3. In position I a film is woundround an inner mandrel and the film is welded to form a tube to producethe inner chamber 1. At station II a film is wound round an outermandrel and welded to form a tube by the production of a side weld seamto produce the outer chamber 2. The inner tubular film can also beproduced at station II and the outer tubular film at station I. This canoptionally also take place at different heights, wherein both tubes mustat least be transported into one plane. A portion of material, forexample plastics material plasticised by heat, is supplied to a diecavity at station III. At station IV the inner mandrel and the outermandrel are introduced, together with the inner and outer tube produced,into a die cavity where the cap is formed from the portion of materialand is simultaneously connected to the two tube ends located inapproximately one plane. Some or all of stations V to VII can beprovided as cooling stations for curing and cooling of the cap. Atstation VIII the die is opened and the finished product removed andtransported away. The described allocation of the production stages tothe stations is to be considered as an example. Any other allocation ofthe processing stages is also possible.

FIG. 4 shows an outer mandrel 14 in which an inner mandrel 15 isarranged so it can be inserted and withdrawn. The outer die of the outermandrel 14 corresponds to the inner die of the outer chamber 2 and thatof the inner mandrel 15 to that of the inner chamber 1 (see FIG. 5also). The inner mandrel 15 and the outer mandrel 14 have cylindricalmandrel projections 16.sub.1, 16.sub.2 which are provided in the cap 3to be attached to form the channels 7.sub.1, 7.sub.2 (see FIG. 1). Whenthe inner mandrel 15 has been driven in the direction of the arrow inFIG. 4 a out of the outer mandrel 14 into its external end position, astrip of film or a portion thereof is wound round the driven-out innermandrel 15 to form a tube which is sealed by a side seam 17, preferablyby welding. The side seam 17 can be produced as an overlapping seamor—as illustrated—as a parallel seam, wherein the start and the end ofthe film winding round the mandrel are aligned parallel to one anotherand then welded to one another for example by means of supplied weldingtongs. With such an embodiment of the side seam 17 with parallel edges,the outer mandrel has a recess 18 which serves to receive the side seam17 projecting somewhat radially when the inner mandrel 15 is retractedinto the outer mandrel 14 (see FIG. 4 b).

In the position shown in FIG. 4 b, both the inner mandrel 15 and theouter mandrel 14 provided with a side seam carry tubular films 11, 12which project slightly beyond the free ends of the respective mandrels14 and 15. The mandrels 14, 15 equipped with tubular films 11, 12 inthis way are simultaneously fed with their free ends into a die cavity19 which reproduces the external form of a cap 3 with seal 8 which is tobe moulded on. A portion of plasticised material, from which the cap 3is to be produced, has previously been fed into the die cavity 19. Owingto a movement of the mandrels 14, 15 into the die cavity 19 or of thedie cavity 19 towards the mandrels 14, 15 or a common movement ofmandrels 14, 15 and die cavity 19 towards one another, the cap 3 ismoulded on by compression of the portion of material. In the process,the channel 7.sub.1 associated with the inner chamber 1 is formed bymeans of the projecting mandrel projection 16.sub.1 and accordingly thechannel 7.sub.2 of the outer chamber 2 is formed by the mandrelprojection 16.sub.2.

FIGS. 6 and 7 show schematically the production of a tube. Theproduction process illustrated is suitable in particular for very thinfilms, for example 75 micrometers (0.075 millimeters) thick. Such astrip of film 21 arranged on a roller 20 is guided over two rotatablefixed deflecting rollers 22, 23 and the start of the strip is wound ontoa spool 24. A mandrel 14 or 15, arranged on a turntable, for example,can be inserted between the two deflection rollers 22, 23 in such a waythat it deflects the strip of film 21 (see FIG. 6) and is partiallycovered by it. In a certain position of the mandrel 14 and 15 with thedeflected strip of film 21, the two welding jaws 19 pivot inwards and,have a shape which is such that the mandrel 14, 15 is completely coveredby the strip of film 21. Each welding jaw 19, 19′ has jaw projections 26which are separated, i.e. provided with a gap 25. The shape of the jawprojections 26 is chosen such that the strip of film 21 covers therespective mandrel 14 or 15 completely and lies with two lateral edgesparallel to one another, which lateral edges project perpendicular tothe mandrel surface. A side seam 17′ of the adjacent lateral edges ofthe strip of film 21 is welded and formed by the welding jaws 19, 19′lying opposite one another. The side seam 17′ formed between theopposing welding jaws 19, 19′ is divided by means of a knife 27 whichcan be introduced into the gap 25 between the jaw projections 26 and 26′which are spaced apart from one another, in such a way that one portionproduces the side seam itself and one portion remains connected to thestrip of film 21 and can be wound on the spool 24.

In the embodiment shown, in the inwardly pivoted state of the weldingjaws 19, 19′, the retaining device for the knife 27 can be introducedinto a guide in one of the welding jaws 19, 191 and can be moved up anddown in the gap 25 of both welding jaws 19, 19′, the previously weldedside seam 17′ being divided, as described above.

When the welding jaws 19, 19′ are pivoted away from the mandrel 14, 15the mandrel 14, 15 now provided with a tube 11, 12 can be transported tothe next workstation. The connected strip of film 21 can be clampedbetween the deflecting rollers 22, 23 (dashed line in FIG. 6) with theseparated side seam portions 28 by the drive of the spool 24. A furtherportion of the strip of film 21 is unwound from the spool 20, whichportion is then looped again—as described above—by the mandrel 14′ (FIG.6) that follows on the turntable for example, and can be provided with aside weld seam 17′. By dividing the side seam 17′ formed a continuousstrip remains which can be gradually wound onto the spool 24 andpartially consists of the fresh strip of film 21 and partially of aportion of strip which has been divided up and comprises the side seamportions 28.

The advantage of this solution lies in the fact that despite the sideseam 17′ being cut by the knife 27 there is always a continuous stripwhich can be guided with a controllable tension by pulling (spool 24)and optionally with additional deceleration of the spool 20.

The corresponding welding devices and film guides can be arranged atdifferent heights to produce the inner tube and the outer tube, can beheight adjustable and/or optionally arranged so as to also be axiallydisplaceable or pivotable.

With sufficient rigidity, for example in a stronger, thicker film,winding round a mandrel can also take place in that an overlapping seam(not shown) can be provided which can be produced so as to be bonded,for example by applying an adhesive or a double-sided adhesive strip, orwelded, for which purpose suitable supply and adhesion or weldingdevices and optionally cutting devices as well would have to beprovided, which are all so familiar to a person skilled in the art thatthey do not need to be described in more detail here.

1. Device for producing the two-chamber containers, with an innermandrel (15) and an outer mandrel (14), wherein the inner mandrel (15)can be inserted into and withdrawn from the outer mandrel (14), a diecavity for the cap (3) and a material feeder for supplying a heatedportion of a thermoplastic polymer material into the die cavity (18) ofa compression mould, characterised in that it has a device for winding afilm round the driven-out inner mandrel (15) and a device for winding afilm round the outer mandrel (14) and advanceable welding devices toproduce longitudinal side seams (17) to produce tubs (11, 12), whereinthe mandrels (14, 15) can both be inserted into and withdrawn from thedie cavity (18) of the compression mould to produce a cap (3) with seal(8) and for connection to the walls of the chambers (1, 2) formed, andin that each mandrel (14, 15) has a projection (16 ₁, 16 ₂) in thedirection of the die cavity (18) for forming a channel (7 ₁ or 7 ₂) inthe cap (3) connected to a chamber (1 or 2) in each case.
 2. Deviceaccording to claim 1, characterised in that the advanceable weldingdevice has two opposing and pivotable welding jaws (19, 19′) which havetwo jaw projections (26, 26′) separated by a gap (25) in each case,wherein a cutting device (27) can be inserted into a withdrawn from thecommon gap (25).